Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]
Balance at the beginning of the year at Oct. 03, 2015	$ 258,142	$ 3,733	$ 4,275	$ 255,711	$ (5,577)
Balance at the beginning of the year ( in shares) at Oct. 03, 2015		14,932,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total comprehensive income	22,698			27,494	(4,796)
Issuance of common stock, net of issuance costs	74,301	$ 474	73,827
Issuance of common stock, net of issuance costs (in shares)		1,897,000
Issuance of tangible equity units, net of issuance costs	84,511		84,511
Purchase of capped calls	(7,935)		(7,935)
Exercise of stock options	$ 2,799	$ 17	2,782
Exercise of stock options (in shares)	68,000	68,000
Stock-based compensation	$ 7,156	$ 12	7,144
Stock-based compensation (in shares)		47,000
Tax benefit (shortfall) from equity compensation	(172)		(172)
Issuance for employee stock purchase plan	1,048	$ 6	1,042
Issuance for employee stock purchase plan (in shares)		24,000
Common stock purchased and retired	(18,414)	$ (77)	(10,595)	(7,742)
Common stock purchased and retired (in shares)		(308,000)
Dividends, $1.20 per share	(18,874)			(18,874)
Balance at the end of the year at Oct. 01, 2016	405,260	$ 4,165	154,879	256,589	(10,373)
Balance at the end of the year (in shares) at Oct. 01, 2016		16,660,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total comprehensive income	34,904			25,084	9,820
Conversion of tangible equity units	0	$ 235	(235)
Settlement of tangible equity units (in shares)		939,000
Settlement of capped calls	$ 0	$ (3)	3
Settlement of capped calls (in shares)	12,000	(12,000)
Exercise of stock options	$ 4,559	$ 28	4,531
Exercise of stock options (in shares)	112,000	112,000
Stock-based compensation	$ 5,620	$ 17	5,603
Stock-based compensation (in shares)		69,000
Tax benefit (shortfall) from equity compensation	(386)		(386)
Issuance for employee stock purchase plan	1,020	$ 6	1,014
Issuance for employee stock purchase plan (in shares)		25,000
Common stock purchased and retired	(1,785)	$ (8)	(1,777)	0
Common stock purchased and retired (in shares)		(33,000)
Dividends, $1.20 per share	(20,415)			(20,415)
Balance at the end of the year at Sep. 30, 2017	428,777	$ 4,440	163,632	261,258	(553)
Balance at the end of the year (in shares) at Sep. 30, 2017		17,760,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total comprehensive income	$ 62,717			61,328	1,389
Settlement of capped calls (in shares)	0
Exercise of stock options	$ 921	$ 5	916
Exercise of stock options (in shares)	19,000	19,000
Stock-based compensation	$ 7,243	$ 19	7,224
Stock-based compensation (in shares)		79,000
Issuance for employee stock purchase plan	1,071	$ 6	1,065
Issuance for employee stock purchase plan (in shares)		24,000
Cumulative effect of accounting change	0		(33)	(607)	640
Common stock purchased and retired	(1,403)	$ (6)	(1,397)
Common stock purchased and retired (in shares)		(26,000)
Dividends, $1.20 per share	(21,394)			(21,394)
Balance at the end of the year at Sep. 29, 2018	$ 477,932	$ 4,464	$ 171,407	$ 300,585	$ 1,476
Balance at the end of the year (in shares) at Sep. 29, 2018		17,856,000